Pressure regulators that reduce or cut off inlet flow of a fluid when the outlet pressure starts to exceed a predetermined maximum and that open or increase flow when the outlet pressure has been sufficiently reduced are well known in the art. Such regulators generally include a coil spring that biases a valve member open, and a pressure-sensing element responsive to excess inlet pressure which closes the valve member. In this arrangement, increasing liquid pressure compresses the spring to force the valve member towards a valve seat. As the valve member approaches the valve seat, liquid flow through the regulator becomes more restricted. When the defined pressure level is reached, the valve member contacts the valve seat to cut off flow. When the output pressure drops below the defined pressure, the valve member moves away from the valve seat and flow resumes. This cycle is rapidly repeated over and over to maintain the output pressure at the desired setting.
Numerous pressure regulating devices teach the use of a coil spring, such as U.S. Pat. No. 3,412,650 by Stang, U.S. Pat. No. 3,547,427 by Kelly, U.S. Pat. No. 3,603,214 by Murrell, U.S. Pat. No. 3,747,629 by Bauman, U.S. Pat. No. 3,825,029 by Genbauffe, U.S. Pat. No. 4,074,694 by Lee, U.S. Pat. No. 4,621,658 by Buezis et al., U.S. Pat. No. 4,744,387 by Otteman, U.S. Pat. No. 5,141,022 by Black, and U.S. Pat. No. 5,732,736 by Ollivier. However, a need exists for a pressure regulator device without a spring coil, thereby resulting in a more reliable device with fewer parts which is easier to assemble and costs less.